This paper deals with the performance analysis of both linear (LE) and widely linear (WLE) equalization processes studied in the symbol spaced mode (SSE) as well as in the fractionally spaced one (FSE). This analysis is evaluated - using Matlab software- in terms of bit error rate (BER) and mean square error (MSE) in a system using a rectilinear modulation of type Pulse Amplitude Modulation (PAM) over a frequency selective channel and corrupted by multiple interferences. Moreover, the impact of the number of external interferers on the behavior of the different equalizers is studied. Thus, simulation results show the outstanding performance of the fractionally spaced mode when compared to the symbol spaced one besides the out-performance of the widely linear processing in both modes. Furthermore, results show the performance degradation for the different studied equalizers when the number of interferences increases